عنوان مقاله [English]
Introduction: Halophytic plants constitute a significant part of the local flora in arid and semiarid regions. Native sheep, goats and camels graze these forages. The Suaeda fruticosa, Seidlitzia rosmarinus and Atriplex leucoclada that are belonging to the chenopodiaceae family, have considerable forage potential in the arid and semiarid rangelands. Overall, these plants are tolerant to drought, and used to reclaim degraded rangeland. In addition, they reduce ground water salinity and improve condition and structure of soil. Meanwhile, there are some secondary metabolites in halophytic plants like condense tannin that effect on consume and performance of the animals. Characteristic of a pasture, climatic conditions the pasture, range management, time of grazing in the pasture, animal characteristics and method of study are factors that all or some can influence yield, chemical compositions and rumen degradability of Halophytic plants. There are a few reports about the nutrition value of Atriplex spp., Seidlitzia spp. and suaeda spp. Therefore, the objective of this study was to evaluate of chemical composition and nutrients degradability of these halophyte plants for dromedary camels.
Material and Methods: This study was conducted in Agricultural Sciences and Natural Resources University of Khuzestan. Two female camels (about four years old) with rumen fistula were used in present experiment. The plants sampling were conducted from three regions of Jofer, Howayzeh and road of Abadan-Khorramshahr on the Khuzestan province in southwest of Iran, an area of approximately 60 Km in diameter. All ranges in term of topography have plain shape, without stone and deep canyons, and with high levels of underground water. The soil of these ranges has salinity characteristic and clay constitution. The study regions climate typified that of south Khuzestan. Annual mean temperature is 24.9°C with average minimum and maximum temperatures ranging from 2.6°C in January to 42°C in August. Precipitation averaged 224 mm per day. The study area had a fair diversity of vegetation types. Four types of these plants named Atriplex leucoclada (AL), Suaeda fruticosa (SF), Seidlitzia rosmarinus (SR) were evaluated individually or in different mixture in completely randomized design. Treatments were, T1, 33.5% AL + 66.5% SR; T2, 100% AL; T3, 66.5% AL + 33.5% SF; T4, 66.5% AL + 33.5% SR; T5, 100% SR; T6, 33.5% AL + 66.5% SF; T7, 66.5% SR + 33.5% SF; T8, 66.5% SF + 33.5% SR; T9, 100% SF. Dry matter (DM), crude protein CP, ether extract (EE), ash, NDF, ADF, lignin, hemicellulose, cellulose, non-fibrous carbohydrates (NFC), neutral detergent soluble fiber (NDSF), total 80% ethanol-soluble carbohydrate (TESC), organic acids, starch and in situ degradability of DM, OM, NDF, CP of each plants were measured.
Results and Discussion: Atriplex leucoclada had the highest hemicellulose, NDF and organic matter among three halophyte plants. The highest concentrations of tannin and oxalate and organic acids were related to Seidlitzia rosmarinus. The SR and AL had respectively highest and lowest dry matter (DM) degradability and effective degradability (ED) (P<0.05). There was not any difference between Seidlitzia rosmarinus and mixture of Seidlitzia rosmarinus + Suaeda fruticose (Treat 7 and 8). Briefly, according to the results of this section, replacement the high levels of Seidlitzia rosmarinus instead of Suaeda fruticose, increase the dry matter degradability more effectiveness than low levels of that. Organic matter degradability of the SR and SF was significantly higher than the AL (P<0.05). The T7 and T2 treatments had the highest and lowest NDF degradability among others, respectively (P<0.05). Crude protein degradability was highest in the treat containing 66.5% SR+33.5% AL (T1), and AL treat had lowest in situ CP degradability percentage. The results were shown that CP degradation rate was faster than DM, OM and NDF in the initial incubation times.
Conclusion: It was concluded that according to DM, OM and NDF degradability, the best plant mix for better feeding of grazing camels are treatments T5, T7 and T8 (without AL); but as protein degradability and chemical composition data, the treatments containing AL (T1, T3, T4 andT6, excepted T2) were the best mix. Therefore, it seems that one of the strategies for improving the digestibility of halophyte plants in camels is mixing these plants with each other, which according to the results of the present experiment, a combination of AL with SR or SF may be caused to more ruminal degradability in feeding of grazing camel and rehabilitation of rangelands.